The present application relates to an inhaler for delivery of medicament from a canister.
Inhalers are commonly used to deliver a wide range of medicaments. The inhaler holds a canister of medicament which is actuatable, for example by compression to deliver a dose of medicament. Some known inhalers are provided with an actuation mechanism for actuating the canister, which may be breath-actuated, ie. arranged to actuate the canister in response to inhalation at a mouthpiece in the inhaler.
Desirably, the inhaler is reusable with different canisters. If the canister is reusable there is a risk of mounting a canister which has already been partly or completely used. This can result in the canister expiring unexpectedly. For example, if the inhaler includes a dose counter, this will give an incorrect measure of the doses remaining if a full canister is assumed when a used canister is inserted. This problem is at best annoying to the user and at worst dangerous if a dose of medicament is needed urgently.